Tail gate device for dump trucks



Sept. l, 1931. A. B. LARsoN TAIL GATE DEVICE FOR DUMP TRUCKS Filed March26, 1950 2 Asheets-sheet 1 A TT ORNE Y.

Sept. 1, 1931. tA. B. LARsoN TAIL GATE DEVICE FOR DUMP TFCKSFiled-'March 2e, 1930 2 sheets-Sheet 2 INVENTOR. Mm @www @WQ/ myATTORNEY.

Patented Sept. l, 1931 y UNTED STATES PATENT OFFICE ALIsoN '.B. LARsoN,or sT. PAUL, MINNESOTA TAIL GATE DEVICE FOR DUMP TRUCKS Applicationfiled March 26, 1930 serial No. 439,062. i

My invention relates to devices for rapid- I have illustrated the usualtype of dump ly unloading so-called dump-trucks of any body made ofheavy plate metal and of type having a dump body mounted pivot- U-shapein transverse section, the front end ally and adapted to be unloaded byraising being closed by a fixed wall and the open 5 the dump body to aninclined position. rear end normally closed by a tail-gate 12 rlhe mainobject of the invention is to prosuspended in said open end by a hangervide an end gate or so-called tail-gate for bar 13, the opposite ends ofwhich are `jourdump bodies and so mounted as to be disnaled in brackets14 fixed one at each of lodged from its original position and eletheupper rear corners of the dump body.

@ vated with relation to the end of the dump Hitherto, when such dumpbody has been @9 body, thus providing a larger discharge raised, fordumping, the tail gate has been i opening than has hitherto beenpossible. released to hang freely from the bar 13 and Other object-s,advantages and the operaany material is dumped out under the gate tionof my improved device are hereinafter as at 15 in Fig. 2.

15 fully set forth and illustrated, in preferred In my device theconstruction is such, that f s form, in the accompanying drawings, inthe tail gate may be used hanging from which,- bar 13 in sockets 14 forordinary dumping Fig. 1 is a side elevation of a motor truck purposes,butV for very rapid dumping cerrearwardly of its engine and cab, adumptain means presently to be described raise 30 body in the lowered orusual position, and the entire gate above its position in brackets m mytail gate operating' device in operative 14 and all materials in thebody readily slide position. The dump body is also shown in out from theend, as the opening thus prodotted lines, in inclined position fordumpvided is practically unlimited (see dotted d ing, and the tail-gatein about extreme open line position of the tail gate in Fig. 1).

3" position. Thus the rear opening may be limited o1 Z Fig. 2 is amodification of Fig. 1 showing unlimited, selectively. For example, tothe dump body inclined and the tail-gate dump out a load of heavy andbulky mateswinging on its hanger bar. rial such as rocks or chunks ofconcrete, the

Fig. 3 is a rear end view of Fig'l. tail gate is raised to highestpossible posi- 32 Fig. 4 is a longitudinal sectional view in tion andall the material is dumped out withenlarged scale, on a vertical planeapproxiout any danger of damage to the tail gate mately centrallythrough the dump body or its pivot bar 13.

and truck frame about as on line 4 4 in My device comprises twocounterpart Fig. 3. beam-levers 16 arrangedin approximately Referring tothe drawings by reference horizontal position, one at each side of anda5 numerals, l have illustrated a truck of near the top edge of the dumpbody, and

which 5 (Fig. 2) is the eab, 6 the parallel pivotally mounted as at 17tosaid body. main frame members and 7 are the rear The rear end of eachbar is bored to receive l wheels, said frames 6 having at their rear theouter end of the tail gate hanger bar t@ ends the bearings 8 for atransverse rock 13, and with my device each bearing castshaft 9 onwhich, between members 6, is ing 14 has an upwardly opening groove 14Gpivotally mounted the parallel stringere 10 in which bar 13 normallyrests while gate of a dump body 11. 13 is thus suspended in positionclosing the The dump body has an end lgate 12 and rear end of the body.18 are side catches 4" the body may be lifted to any required in on thegate arranged to be held removably clined plane by suitable power meansnot by a latch 19 further held by a pull rod shown, the end gate 12provided with re- 20 (see Fig. 1) and a lever 21. These latter leasingmeans near its lower parts to allow details are well known in the art.

it to open and dump out the material in the The front end of each lever16 is bored to dump body when raised. provide a bearing 22 for the upperend of l a U-shaped bar member 23, said bar extending downwardly at bothsides of the dump body, thence directed inwardly and its lower partcomprising a straight section 23S, always under the stringers 10 andcrossing them transversely. 24 are a pair of counterpart plates fixedone on each stringer 10, extending belowv the latter and having arearwardly directed notch 24N. Both said notches receive the U-bar part28S simultaneously, the bar being suitably retained in this position bymeans such as an oscillatable bar extending longitudinally of one orboth stringers toward the front of the truck, the rear end of such bar25 having a downward finger 25E` to engage bar 23S and draw it into thenotches 24N when bar 25 is pulled forward by means such as a lever 26pivoted on a transverse shaft 27 journaled in the stringers 10.

Obviously, when lol-bar 23 is held in notches 24N it is stationary withrelation to the dump body, and if the latter is raised for dumping thehanger bar 1S of the gate remains in its sockets MG and gate 12 willswing open with its fulcruin in the brackets 14: (see F ig. 2). rlhis isa suitable condition when the material to be dumped is not coarse andmust or can be dumped slowly.

For dumping rapidly l provide means for disengaging the til-bar 23 fromthe position just described and make it stationary with relation to thetruck frame members 6, as follows: Assuming that -the dump body is inlowered position shown in Fig. l; 28 are a pair of upright plates fixedat 29, one on each truck frame member '6 and each havinga forwardlyopening notch 28N registering horizontally with the rearwardly openingnotches 24N of the plates To connect the ld-bar part 23S rigidly butpivotally with the frame parts G the part 23S is moved rearwardly fromposition above described until it stops in the bottom of the notch 28N(see full line position of part 23S designated 23S in Fig. il). This isdone by swinging lever 26 forward causing rod 25 to move rearward andanother bar 30 mounted on frame G and provided with an upright fingerBOF is pushed rearward simultaneously, said finger 30E bearing againstpart 23S and pushing it rearward. The pushing action on rod 30 is causedb a cam lever 31 pivoted on shaft 27 mounted transversely between frontparts of stringere 10 as described.

Now it will be readily understood that after U-bar part 23S has beenpushed rearwardly as described it is retained pivotally in the bottomparts of notches 28N and the entire ll-meinber 23 is held stationarywith relation to the truck frame. Consequently, when the dump body isthen raised the member 23 is retained p ivotally in the notched parts ofthe frame plates 28. As the dump body raises the pivots 17 of levers 16move rearwardly as from 17 to 17 X in Fig. 1, the pivotal connections 22of members 23 and 16 are drawn downwardly with relation to pivots 17 andthe rear parts of the levers 16 are raised simultaneously, with relationto the bearings 1d at the rear upper corners of the dump body. Thus thesuspension bar 13 of the tail gate is raised out of the brackets 14 andthe gate is suspended over the rear open end of the dump body.Obviously, the rear end of the dump body is now wide open and allmaterial of any nature therein slides out absolutely unimpeded, the tailgate being raised bodily above the rear end of the dump body. (See Fig.1). lWhen all material has thus been dumped the body is lowered and thetail-gate drops back to its original position and suspended from shaft13 which drops to resting position in the brackets 14: as shown in fulllines in Fig. 1.

The sliding bar 30 above described may be provided, one at each framemember 6 and both connected by a cross bar 32 which is in the path ofcam-lever 31 which pushes both rods 30 forward when said cam is swungforward by proper movement of lever 26, to push the U-bar 23 rearwardfor the purpose described.

rlhe details of my device in a preferred form and its operation, havenow been fully disclosed. It is obvious that a number of modificationsmay be embodied. For example, the U-member 23 need not necessarily beU-shaped, but made in two parts, each manipulated by the respective pushand pull rods 253O simultaneously.

Means other than said rods 25-30 may also be used to cause pivotalconnection of the Ll-bar 23 or corresponding parts, to either the truckframe or to the dump body sills 10 as the case may be.

I claim:

1. In a tail-gate opening device for tiltable dump truck bodies of theclass described, a tail-gate pivotally suspended from a shaft andnormally closing an end of the dump body when the latter is in loweredposition, pivot brackets for said shaft mounted at the upper corners ofthe open end of the dump body, beam lever means pivotally connected withsaid shaft and extending forwardly therefrom, means connected with theforward parts of said beam levers and extending downwardly to the underside of the dump body, said latter means securable selectively andpivotally to the support frame means of the dump body to make the beamlever means inoperative when the dump body is elevated, or pivotallyconnected with a stationary object below the dump body to cause downwardpull on the said beam lever when the dump body is tilted upwardly, saidpivot brackets on the dump bodies provided with upwardly opening groovesfor said tail-gate shaft to rest in, said beam levers fulcrumed to theside of the dump body and said means connected with the forward parts ofthe levers comprising a U-shaped member extending under the dump body,said U-member arranged when in fixed position relative to the dump bodyto hold the beam levers and the tailgate shaft in original position withthe latter in pivotal position in its brackets.

2. In a tail-gate opening device for a motor vehicle having elongatedparallel main frame members, a dump body pivotally mounted on the saidmain frame and means for tilting said dump body; a tailgate hingedlysuspended at the end of the dump body lowered by its tilting movement,counterpart beam levers fulcrumed to said body at both sides eachpivotally connected to the tail-gate at its rear end, a connecting barextending downwardly from the front end of each beam lever, thenceinwardly horizontally toward the truck frame, vvertically arrangedplates on the under side of the dump body and like plates fixed on thetruck frame, the first plates having rearwardly directed notches and thelatter plates corresponding forwardly directed notches and said notchesof both sets of plates arranged in horizontal alineinent when the dumpbody is in lowered position, and means mounted on the dump body adaptedto be manipulated to move the lower horizontal parts of said connectingbars simultaneously and as required into pivotal position in the notchesof the plates fixed to the dump body or the notches of the main framemembers, for the purpose described.

3. The structure specified in claim 2 in which said connecting barmanipulating means comprise a fixed transverse shaft rotatably mountedin an end part of the dump body, a hand lever in accessible positionthereon, a crank on said shaft and a rod mounted longitudinally of thedump truck and arranged to engage the lower connecting bar partdescribed to pull it forward when said crank is operated in onedirection by the hand lever, and a cam arm on said transverse shaft,means on the truck frame and oscillatable longitudinally thereof bymovement of said cam arm to push the lower connecting bar part describedrearwardly.

In testimony whereof I aiiix my signature.

ALISON B. LARSON.

